The flex-shrink property must be animatable https://drafts.csswg.org/css-flexbox/#flex-shrink-property Here its a simple test case: https://codepen.io/cl0p3z/pen/WNvWvEb Works on Chrome and Firefox. Fails on WebKit. This its tested by WPT css/css-flexbox/animation/flex-shrink-interpolation.html
*** Bug 217901 has been marked as a duplicate of this bug. ***
Created attachment 411737 [details] Patch
Comment on attachment 411737 [details] Patch r=me. Please wait for EWSs results before landing.
Committed r268718: <https://trac.webkit.org/changeset/268718>
<rdar://problem/70476960>